Terrible wifi power consumption Librem 13v3

Hardware
1

I’ve been seeing terrible wifi power consumption on my Librem 13v3.
I’ve tried reloading the driver with modprobe ath9k blink=0 btcoex_enable=0 bt_ant_diversity=1 and purism-power-optimisations.service is active as well.
I’m seeing ~5W of power consumption on powertop with all tweaks enabled. This statistic seems crazy; it’s consuming more energy than my display backlight. How can I reduce its power draw?

2

If 5W what powertop reports or is it the difference between HKS on and HKS off?

The powertop Watt readings are wrong for most peripherals and do not add up.

Cheers
nicole

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3

Ah, I’m getting the 5W number from powertop’s Device stats tab. I’m trying to figure out why my laptop is burning through battery, especially while suspended. Unplugged it last night from a full charge and it drained empty in 6 hours according to Power Statistics. Sorry, I’m not sure what HKS is…I’ve tried to reload the ath9k module with the ps_enable=1 flag; is that what you’re referencing?

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HKS = Hardware Kill Switch

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Gotcha, I’ll flip the switch and see what that does. Thanks!

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Ok, so HKS does what it says on the tin: power consumption from wlp1s0 disappears. Turning it back on reenables the device and it starts consuming power again. I’ll keep an eye on draw.

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7

Sure, the HKS disables the device. Neverthelesse the Watt value in pwoertop is nothing more than a guess out of thin air, there is nothing in the device that could measure the energy on the M.2 card.

About 10% battery power draw in suspend to RAM is pretty normal, take into account that the DDR4 RAM needs to be refreshed all the time and some other parts of the system are also still powered. A laptop is not a mobile phone… Also make sure not to have any USB devices attached to it while in suspend, these may draw significant power too if they do not go into standby.

Cheers
nicole

1 Like
8

Good to know regarding Powertop measurements. I honestly thought they were accurate. Definitely, 10% makes sense to me, but 100% in 6ish hours did not. I think you may have solved my problem, and it was in a completely different place. I do have a usb wifi nic attached for doing…experimenting…with a Kali VM. No idea that attached USB devices didn’t go into standby! I’ll unplug it and give it a go tonight. Thanks for the help, Nicole!

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Just so we are on the same page - 10% per hour, right? So within 6h it would mean -60% = 40% left.

The standby of USB devices also depends on the devices themselves. Some do, some don’t, some that do don’t wake up properly anymore, some do.

You should definitely also have a look at the “Tunables” page in powertop and turn everything to “good”, which also includes power saving modes for USB devices. Just keep in mind that some may not like it so watch your system after doing that.

Cheers
nicole

2 Likes
10

Actually I meant 10% over the course of a night, and it looks like that was the result! Here was my procedure:

  1. All powertop tunables were set to “good”
  2. Laptop was charged to 100%
  3. ath9k driver reloaded with ps_enable=1 (is there a way to load it with flags like this by default?)
  4. Unplugged my realtek usb wifi nic
  5. Suspended

After 11 hours of suspend I’m at 89% battery, which means drain is ~1% per hour! I guess my realtek card was actually the battery hog all along.

Thanks for the help!

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